Martha Alexander 1840s-50s Harris Co. GA

I'm looking for information on a Martha (Unknown) who was born Abt. 1815 in Ga. She married an Alexander man, given name not known, in Harris Co., GA, date unknown but thought to be abt 1830-31.They moved across the river to Chambers Co. AL prior to 1847.Mr. Alexander died in mid-1840s leaving her and three children: SUSAN, b. 1832; m. JOHN J FARLEY, August 16, 1850, Chambers Co Al.; WILLIAM, b. 1836; and SARAH, b. 1838.Martha next married my ancestor, John Bartley on July 08, 1847 in Lafayette, Chambers Co., Al.John died Dec. 8, 1847 in Chambers Co. Martha Alexander Bartley is next found back in Harris Co. One or two of John's children lived with Martha for a while but then lived with their older siblings.Next Martha married James Roper on 1/9/1851, by H Gilmore, MG, HW Roper, LS, (Taproots, Vol. 8, No 1, July 1970, p. 27.)Would like to know the following: Martha's maiden name and information about her parents; Mr. Alexander's given name and his parents; the history of Martha after she married Mr. Roper (i.e. where moved, died, buried?) Many thanks, Paul